<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8" />
    <title>双飞翼</title>
    <style type="text/css">
        * {
            box-sizing: border-box;
        }

        .main-inner {
            margin-left: 100px;
            margin-right: 100px;
        }

        .content {
            overflow: hidden;
            /* padding-left: 100px;
            padding-right: 100px; */
        }

        .content>div {
            float: left;
            /* position: relative; */
        }

        .main {
            width: 100%;
            height: 100px;
            border: 1px solid red;
            background-color: yellow;
        }

        .left {
            width: 100px;
            margin-left: -100%;
            /* right:100px; */
            height: 100px;
            border: 1px solid #000;
            background-color: crimson;

        }

        .right {
            width: 100px;
            /* margin-right: -100px; */
            margin-left: -100px;
            height: 100px;
            border: 1px solid #000;
            background-color: chartreuse;
        }
    </style>
</head>

<body>
    <div class="content">
        <div class="main">
            <div class="main-inner">main</div>
        </div>
        <div class="left">left</div>
        <div class="right">right</div>
    </div>
</body>

</html>